1. Field of the Invention
The invention is based on a power circuit-breaker according to the preamble of claim 1.
2. Discussion of Background
Patent Specification EP 0 374 384 31 discloses a power circuit-breaker which is filled with SF.sub.6 gas. In the case of this power circuit-breaker, the quenching gas which is required for blowing out the arc is produced on the one hand by the arc itself and on the other hand, in addition, by a piston/cylinder arrangement. The piston/cylinder arrangement has a stationary piston. The pressure which is produced by compression in this piston/cylinder arrangement rises approximately in proportion to the travel of the moving cylinder, provided no pressure flows out of the piston/cylinder arrangement during the compression period.
In the case of this power circuit-breaker, only that pure SF.sub.6 gas which is already present in the piston/cylinder arrangement at the start of disconnection is compressed in the compression period during the disconnection process. If it is intended to increase further the disconnection capacity, then this could admittedly be achieved with the aid of an enlarged piston/cylinder arrangements but this would lead to an arcing chamber of larger dimensions, which would considerably increase the cost of the power circuit-breaker. In addition, a larger piston/cylinder arrangement would also require a stronger and thus more expensive drive.